Speaking of ChatGPT. I asked AI for statistics on the drop-off in goals per game over a career, and here's Gretzky, Jagr and Ovechkin (as of 2023 in its data). I asked it to use their first 80+ game season and their last 70+ game season to keep it realistic:
Gretzky: 0.625 goals per game -> 0.33 gpg
Ovechkin: 0.64 gpg -> 0.55 gpg (2022-23. This is 0.65 this season)
Jagr: 0.44 gpg -> 0.33 gpg
And using Top 5 (Hull, Dionne), the average drop-off has been about 0.2 gpg compared to the player's first full season.
So if we assume a 1400 game career, here's what the AI would project to some active players, with a linear downwards trend in gpg according to the above:
Draisaitl: 490 goals
MacKinnon: 490 goals
McDavid: 518 goals
Matthews: 686 goals